Improve compatibility with the IRCCloud Slack gateway

main.go

@@ -147,9 +147,8 @@ type Data struct {
 	ImageUrl    string      `json:"image_url"`
 	Type        string      `json:"type"`
 	Player      string      `json:"player"`
-	ThumbUrl   string      `json:"thumb_url"`
-	Footer     string      `json:"footer"`
-	FooterIcon string      `json:"footer_icon"`
+	Service     string      `json:"service"`
+	ServiceIcon string      `json:"service_icon"`
 	Ts          int         `json:"ts"`
 }
 
@@ -209,31 +208,23 @@ func buildData(in InternalData, oEmbed OEmbed, providerFallbacks []func(*Interna
 
 	for _, fallback := range providerFallbacks {
 		out.Color = coalesce([]string{in.metaThemeColor, in.urlProviderMetaThemeColor})
-		out.Footer = coalesce([]string{oEmbed.ProviderName, in.ogSiteName, in.urlProviderOgSiteName, in.urlProviderMetaTitle, in.urlProviderTitle})
-		out.FooterIcon = resolve(in.url, coalesce([]string{in.linkFavicon, in.urlProviderLinkFavicon, in.urlProviderIconPng, in.urlProviderIconIco}))
-		if out.Footer != "" && out.FooterIcon != "" {
+		out.Service = coalesce([]string{oEmbed.ProviderName, in.ogSiteName, in.urlProviderOgSiteName, in.urlProviderMetaTitle, in.urlProviderTitle})
+		out.ServiceIcon = resolve(in.url, coalesce([]string{in.linkFavicon, in.urlProviderLinkFavicon, in.urlProviderIconPng, in.urlProviderIconIco}))
+		if out.Service != "" && out.ServiceIcon != "" {
 			break
 		}
 		fallback(&in)
 	}
 
-	var largeImages []string
-	var smallImages []string
-	if in.twitterCard == "summary" || in.twitterCard == "summary_large_image" {
-		largeImages = append(largeImages, in.twitterImage)
-	} else {
-		smallImages = append(smallImages, in.twitterImage)
-	}
-	largeImages = append(largeImages, in.ogImage)
-	smallImages = append(smallImages, in.ogImage)
+	var images []string
+	images = append(images, in.twitterImage)
+	images = append(images, in.ogImage)
 	if in.rawType == "image" {
-		largeImages = append(largeImages, in.url.String())
-	}
-	// Only use favicon as thumbnail icon if we don’t already use it for the footer
-	if out.Footer == "" {
-		smallImages = append(smallImages, in.linkFavicon)
+		images = append(images, in.url.String())
 	}
 
+	out.ImageUrl = resolve(in.url, coalesce(images))
+
 	hasType := func(formats []string, types []string) bool {
 		for _, format := range formats {
 			for _, t := range types {
@@ -265,9 +256,6 @@ func buildData(in InternalData, oEmbed OEmbed, providerFallbacks []func(*Interna
 		out.Type = "article"
 	}
 
-	out.ThumbUrl = resolve(in.url, coalesce(smallImages))
-	out.ImageUrl = resolve(in.url, coalesce(largeImages))
-
 	buildField := func(title string, value string) {
 		const MaxShortFieldLength = 32
 		value = strings.TrimSpace(value)